New Belts, New Whine

[EMBPilot]

First off,
thanks to Vinman, for his time, patience, garage, tools and did i mention patience?

and thanks to this board for being such an awesome resource.

The job took about 4 hours. with only one surprise... it looks as if one of the PO's took off the auto tensioner and replaced it with the roller type tensioner. it was a welcome surprise.

using Arnworkx tools and clarks garage articles close at hand we got the old belts off. they looked to be in really good shape.

a few notes though.

we tensioned the belts using bruces tool. using his tool the balance belt felt just TOO loose. I mean really loose, very wobbly, so we tensioned it somewhere between what bruce's tool said and where we felt comfortable (little tighter than what bruces tool recommended).

after driving the car home, only about 10min or so... you can hear a distinct whine. sorta like a supercharger. most pronounced at idle, but it changes with engine speed.

could the whine be the balance belt?

the cam belt tension was right on the money with bruces tool.

the idle roller for the balance belt was stiff. you could turn it with your fingers but it felt as though it was rubbing on the belt below it, but it isnt. its just stiff to turn. its sitting just about half a millimeter below the balance belt span.

actually, two more things...
what should the tension be for the alternator belt? we set it using the twist method, i suspect thats okay.

the rollers and WP seemed to be okay.
the idle roller for the cam belt had a very suttle lip on it.

thoughts comments ect...

i feel muuuuch better about all this now so taking it down again, to retension i feel comfortable with.

[VINMAN]

Kev, did the whine get worse as you drove home?
Happy to help you out. Glad it went well.

[EMBPilot]

actually vinny i think it got quieter.

i just ordered up new power steering, alternator belts, and two new idle rollers. (cam and balance)

...and tires

[944mech]

My '83 is doing the same whine noise like a supercharger and has been since i put the engine back together in august
I was reading somewhere that you have to have the tensioner's a certain amount of space apart from the lip of the cover or something like that
Does anybody know what causes this noise?

[Porsche-O-Phile]

Belt whine is normal on freshly-installed belts. Make sure to do the retension at 1,500 miles or thereabouts - the whine will eventually diminish a little.

The belt should feel a little loose - keep in mind that the aluminum engine expands by almost a full half inch when everything heats up.

[Ford-o-phobic]

Originally posted by Porsche-O-Phile
keep in mind that the aluminum engine expands by almost a full half inch when everything heats up.

Really?

[EMBPilot]

okay thats a start, i'll attempt a retension on a completly cold engine, once i replace the cam and balance idle rollers on tuesday. in the meantime the car will sit....

[Techno Duck]

Its completley normal for a new roller to be stiff to turn. Rule of thumb is if you can spin a roller to 'infinity' (IE you spin it and it keeps on going and going) then the roller is shot. But of course like anything use your judgement when changing. If its excessivley hard to turn then thats not good either.

Based on what your saying, i think your balance shaft belt is a little too tight. You should be able to twist the belt with reasonable effort just past 90 degrees with the engine completley cold.

Alternator belt should have aprox. 4mm of deflection at the longest span. Its alot tighter than you think it should be.

Alot of what i am telling you involves the calibrated hand method and is subjective. Again, judgement is everything.. .

Congratulations on the belt job though..you just saved yourself about $500 in labor.

[Panzer909]

New belts have always made a whine in my experience. If you're losing sleep over them, get them tensioned by a shop knowing you did the big job for the most part yourself. Remember - a whine means tightness.


BTW, congrats on your first belt job, Kevin!!!!!!!

[Eldorado]

hpaulb helped me with my belts last year.. and i just got a porsche shop to retension them a couple months ago... $60 cash and i was out the door... less than 1 hr labour... if you want peace of mind, you could go that route, as johnny suggested.

[Razorback1980]

I agree with Panzer...tight belts = whine. I haven't used Bruce's tools to set my balance shaft belts before, so I don't have any experience to draw from as to whether going past the tools recommendations made the belt too tight. I use the 90 degree method. It will probably quieten as the belt stretches a bit. If after the retension, it whines louder again, I might back it off a little.

That first one is scary, isn't it? I think it may be that you know the consequences if you screw it up. Not so bad after you have done it once...but it's better if you can have someone show you. Pretty soon, you may just forget about the flying and open a Porsche shop! Good work Kevin.

That was a cool thing Vinny.

[EMBPilot]

thanks guys! your not kidding Tom, i took a long deep breath before turning that key! i may just back off the balance belt a little bit, and i'll do a retension on both when i install the two new idle rollers. Based on what Jon said i may need to tighten the alternator belt as well.

oh, i left out the best part of the story... Vinny, initially tightened the belt using the twist method. We took a reading from the tool, using his fingers alone he got the cam belt within .010 units of the correct tension!

Kevin

[VINMAN]

I have magic fingers!

Kevin idler is definatley on its way out. As far as the balance belt. after setting the tension with bruces tool, it had almost an inch of play on it, enough so it was hitting the water pump pulley. I dont care what the reading was, that is way too loose.

[VINMAN]

I know I'm gonna get flamed for this.... but I think people get way too carried away and uptight about the belts on these cars.

[EMBPilot]

i agree something was up with the tension on the balance belt, when it was showing correct based on the tool it would easily touch the WP. im going to check it like you showed me when i put the new idlers on, twist it just over 90.

[JonA]

I just did my belts (for the first time) and ended up with the whine. Rechecked everything multiple times and talked and e-mailed back and forth with Bruce. After 200 miles the whine is still there. But belts run cool and the twist method tells me I'm pretty close. I'm not going to worry about it for a few more miles and then I will retension everything.
There was a little whine from the old belts when I bought the car and first drove it home. I wish I had paid more attention but I'm pretty sure it wasn't as much as I'm gettin now.
There's been so much posted about the belts, I think we're all gettin a little neurotic.......

Jon.

[Panzer909]

I agree. My car had a whine until I got it retensioned by my shop the last time the belts were done......eh......let's just say too long ago.

Bruce Arnn recently had a small video clip on his site to tell people what a car sounds like with a belt way too tight. I remember hearing the clip and quietly thinking to myself: "Jeez, that's what my car has always sounded like when it first starts up!"

The clip can be found near the bottom of this page: http://www.arnnworx.com/tensioningbelts.htm

[EMBPilot]

okay guys, i took the car back apart. I double checked the tension on the cam, its was 100% on the money. i still need to get the two idle rollers in there when they come tomorrow, but now down to business.

If i follow bruces directions exactly here is the outcome.
with the BB resting at its "set tension" if you push down on the BB with one finger just under the water pump and hold a ruler next to the belt, it will deflect DOWN half of an inch (.5").

[Techno Duck]

Man i really should double check my balance shaft belt.. cause everyone does say it sounds like i have a super charger .

Have you tried doing the twist method yet? How did that work out?

[VINMAN]

I think thats about how much play we had on it. When it was set to the specified tension it had way over an inch of play